<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const p1 = new Promise((resolve,reject)=>{
            try{
            throw new Error('网络错误')

                setTimeout(()=>{
                    // resolve('异步任务成功')
                    // reject('异步任务处理失败')
                })
            }catch(e){
                reject(e)
            }
        },2000)

        p1.then(value =>{
            
        })

        //catch的返回值和then的规则一样
        p1.catch(reason =>{
            return new Promise((resolve,reject)=>{
                resolve('sasa')
            })
        })
    </script>
</body>
</html>